To be considered omnivorous, a bird does not need to eat all possible types of plant or animal foods, nor do the foods need to be eaten at the same times, but the overall diet must include significant amounts of both. Diet type classification is typically only applied to mature, adult birds - young chicks may have significantly different diets to obtain the necessary proteins, minerals and nutrients for proper growth. Many mature birds also change their diets seasonally, but if they eat both plant- and animal-based foods during the year, they are considered omnivorous.

By the broadest definition, most birds could be classified as omnivores because they eat insects for a protein source even if much of their diet is plant-based. When insects or other animal materials are only a small or irregular fraction of a bird's diet, however, they may be classified as a different diet type.

Birds known to have omnivorous diets that are more equally balanced between plant- and animal-based foods include many types of ducks, woodpeckers, orioles, jays, thrushes, turkeys, blackbirds, gulls and other indiscriminate eaters.

How Omnivorous Diets Change

Omnivorous bird species often change their diet seasonally for whatever food sources are most readily available.

For many birds, this means eating insects in the spring and summer when bug populations are booming. In late summer fruits may be more readily available as crops ripen, then in fall seeds and grains may be most abundant. In winter, any available food could be eaten, and birds may even eat nuts or grains they have cached. This dietary adaptability allows birds to have a wider range of choices and take advantage of more food sources for better survival, particularly for resident species that do not migrate to different locations as local preferred foods dwindle.

Birds may also change their diets at different life stages based on changing nutritional needs. During the breeding season, for example, female birds often consume more calcium for healthier egg development. More animal-based foods may be present in birds' diets when they are molting and need more protein for for proper feather growth, and higher calorie, fat-rich foods are often preferred during migration, when the extra energy provides critical fuel for migratory species.

Many juvenile birds eat greater amounts of animal-based foods for the higher protein those foods provide, which improves growth and development. As the birds mature, they may eat a more varied diet or could even switch to a completely herbivorous menu, in which case they would not be considered truly omnivorous.

Feeding Omnivorous Birds in the Backyard

Birders can take advantage of birds' varied diets by offering a wider range of foods in their backyard to attract hungry birds. The best foods to offer to cater to omnivorous birds include...

By catering to a range of tastes, backyard birders can attract a much wider variety of birds to their feeders. To make the foods even more attractive, it is important to use different bird feeder styles, keep feeders accessible to multiple birds and practice safe bird feeding habits.

Regularly cleaning feeders, installing baffles to deter other wildlife and generally making the entire yard bird-friendly will help attract many omnivorous birds to the backyard buffet.